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Thread: 95 E36 M3 Heater Core Delete Coolant Hose Question

  1. #1
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    95 E36 M3 Heater Core Delete Coolant Hose Question

    Greetings,
    I've just deleted the heater core in my dedicated track car and will be reworking the cooling hoses coming out of the back of the head. I've found several threads discussing this:

    http://forums.bimmerforums.com/forum...d.php?t=869761

    http://forums.bimmerforums.com/forum....php?t=1289929

    http://forums.bimmerforums.com/forum....php?t=1608526

    None of the threads seem to provide a definitive optimal solution.

    My question is:

    Coolant block off plate on the back of the head?

    OR

    Reroute the hoses from the back of the head?

    Thanks in advance!!

  2. #2
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    coolant blockoff plate at the back of the head, and then eliminate the entire "spider hose" and run a single hose from the front head outlet to the expansion tank.

    -Mike
    IG: mikevanshellenbeck

  3. #3
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    I run a block off plate and never had any issues or change in running temp
    http://www.hardmotorsport.com/BMW-S5...MSCoolBOFF.htm
    http://www.hardmotorsport.com http://Facebook.com/HardMotorsport

  4. #4
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    Almost everyone in club racing uses the block off plate. I have run it for four years and motor is still going. Never overheated. On the factory set up, when the heater is not in use the valve closes off the flow through the heater core so you are not doing anything that is not designed for.
    Patrick Spikes

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  5. #5
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    what is "optimal" may be too difficult to plumb properly.

    What is "accepted" to be the go-to setup is a block off plate, and single hose run from the timing cover to the expansion tank
    "Torque is like cowbell... you can never have too much." - Michael Cervi


  6. #6
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    Block off plate at the back of the head is "optimal". As pointed out, this is how the system is designed to function. When the heater valves are opened, they pull hot water from the back of the head and route through the heater core and return it to continue it's path to the expansion tank. When the heater valve is closed, the water continues it's path through the head. You do not want to pull this water from the back of the head and return to the timing cover port. This will recirculate the hot water without first running it back to the radiator to cool.

  7. #7
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    although not directly related...

    This has some relevant data. (opinions) - AS well as some good images showing options.

    http://forums.bimmerforums.com/forum/showthread.php?t=959297

    Rich

    Quote Originally Posted by Michael9218 View Post
    Block off plate at the back of the head is "optimal". As pointed out, this is how the system is designed to function. When the heater valves are opened, they pull hot water from the back of the head and route through the heater core and return it to continue it's path to the expansion tank. When the heater valve is closed, the water continues it's path through the head. You do not want to pull this water from the back of the head and return to the timing cover port. This will recirculate the hot water without first running it back to the radiator to cool.
    I hear what you are saying, but. in OEM configuration, coolant flows from the rear of the block to the heater core, then into the "spider" which is connected to the rear of the timing cover and the coolant overflow. If I understnad correctly, there is not really a constant FLOW THROUGH the overflow. When I added a heater core back into my car, I ran a hose out of the rear of the head, into the heater core, then into a Wye connecting the expansion tank and rear of the timing cover. There were not really any other feaible options, and this is really the only possible config as layed out with a euro style rigid tube. I dont know what the internals look like under the timing cover, but it looks like the coolant dumps into the main flow of the water pump.

    Are you thinking that could increase overall system temps?

    Rich
    Last edited by Motomeister13; 01-23-2012 at 10:12 AM. Reason: Automerged Doublepost
    #413 SE36

  8. #8
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    Quote Originally Posted by Motomeister13 View Post
    I hear what you are saying, but. in OEM configuration, coolant flows from the rear of the block to the heater core, then into the "spider" which is connected to the rear of the timing cover and the coolant overflow. If I understnad correctly, there is not really a constant FLOW THROUGH the overflow. When I added a heater core back into my car, I ran a hose out of the rear of the head, into the heater core, then into a Wye connecting the expansion tank and rear of the timing cover. There were not really any other feaible options, and this is really the only possible config as layed out with a euro style rigid tube. I dont know what the internals look like under the timing cover, but it looks like the coolant dumps into the main flow of the water pump.

    Are you thinking that could increase overall system temps?

    Rich
    What you've described above as your solution to add back in a heater core is replicating the OEM configuration, so you should be okay.

    My assumption is that the water returns from the heater, and the timing cover, to the expansion tank. My comment above is in reference to where people disconnect the heater hose and route the water from the port at the back of the head to the timing cover and remove the expansion tank return. You could return the water from the back of the head to the wye directly by bypassing the heater core, but there's no point. Let the water continue it's path through the head, and simplify your plumbing. Pulling the water out of the back of the head without using it for a heater core is wasting it's cooling capacity in the head.

  9. #9
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    Also another user of the block-off plate.

    Does anyone have a specific hose they run to the expansion tank? I had the "spider" tubing blocked off and want to eliminate it all with the OBD1 style adapter.

    Regular heater hose OK or something special would be better?
    -Luke

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  10. #10
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    Quote Originally Posted by LukeP View Post
    Also another user of the block-off plate.

    Does anyone have a specific hose they run to the expansion tank? I had the "spider" tubing blocked off and want to eliminate it all with the OBD1 style adapter.

    Regular heater hose OK or something special would be better?
    IIRC, I ordered a second return to expansion tank hose (the long one) and cut to fit. It had the correct ID and even had a couple useful bends.

  11. #11
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    I used one inch heater hose from napa which fit the engine side and the euro overflow bottle.
    Patrick Spikes

    Guinness, not just for breakfast anymore

  12. #12
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    Thanks for all the responses!

    This is what I ended up doing:

    I cut out the spider hose leaving as much of the hose coming out of the back of the thermostat as possible






    Then I joined the hose coming out of the back of the thermostat with the hose going to the overflow tank:







    I also attached the block off plate at the back of the head:




  13. #13
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    Thanks nschaeff for the info.

    How are things running for you since deleting the heater core?

    This is on my to-do list next... and please let me know if my 99 M3 will be any different than yours...
    Last edited by JSA; 03-02-2012 at 09:24 PM.

  14. #14
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    Quote Originally Posted by JSA View Post
    Thanks nschaeff for the info.

    How are things running for you since deleting the heater core?

    This is on my to-do list next... and please let me know if my 99 M3 will be any different than yours...
    OBDI has a rubber coolant hose running from the timing cover to the firewall. OBDII has a hardline running from the timing cover to the firewall. You can either plug the rubber hose at the firewall, or convert to an OBDI pipe.

    http://store.bimmerworld.com/obd-i-c...pipe-p959.aspx

    I bought this, not knowing the OBDI/OBDII differences.

    http://www.tcdesignfab.com/products/...heatercore.php

    Needless to say, it came with everything I needed, OBDI or OBDII. Ran my temp sensor in the block-off plate and I see 180-200 degree temps on and off track.

    EDIT:
    Content of the kit since not listed on the site:
    Hose plug (For OBDII cars)
    Block-off plate which has an 1/8"NPT port
    1/8" NPT plug (If you don't want to use the port)
    Block-off plate gasket
    Firewall panel (Optional)

    I think it came with new bolts and washers for the block-off plate but i don't really remember. Awesome kit and panel.
    Last edited by RatedM3; 03-02-2012 at 09:42 PM.

  15. #15
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    [QUOTE=nschaeff;23669014]Thanks for all the responses!

    This is what I ended up doing:

    I cut out the spider hose leaving as much of the hose coming out of the back of the thermostat as possible






    Then I joined the hose coming out of the back of the thermostat with the hose going to the overflow tank:







    I also attached the block off plate at the back of the head:



    w what u do with other two hoses from the spider hose just plug other end where they go? thanks

  16. #16
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    This is all very good but I still have some questions regarding some of the parts the hoses connet to.
    http://i.imgur.com/92k9h.jpg
    So I see the idea is to get rid of the “spider” and just connect hose 1 together after it has been cut. Ok but what about hose 4 & 5, 4 comes from the engine goes into some sort of sensor that sits inside the OEM airbox, 5 goes into the throttle body then comes out as hose 3 which roots back into the “spider”. Now I see what one of the guys has done when he said he just connected hose 2 to the back of the engine and looping the entire thing together. I don't want to do that as I want to make it look neat.

    Answered: Apparently the sensor in question mark is useless and it's safe to be removed. Hot or cold air hits the copper (no electrics) and the thermostat can operate quicker by opening or closing instead of waiting for it's default values. It's a gimmick!

    Question 2: If I delete it do I just plug the hole in the engine where hose 4 is running in the picture?

    Answered: Throttle body heating not cooling, is designed to stop the butterfly from frosting and getting stuck.

    Question 4: Why did you guys buy the block of plate, isn't it easy just to make one from a piece of metal?

    Question 5: I guess I won't need to buy any hoses if I just cut the spider and connect the main number 1 together. What adapter did you use to do so? Looks good in the photo

    Guys question 2 is very important in order to fully proceed. I have started taking the lot apart and I believe blocking hose number 4 is safe to do. It was designed as an exit for the air thermostat sensor and throttle body which loops back in the the spider anyway.
    Last edited by S1Driver; 09-05-2012 at 07:21 AM. Reason: Found some answers

  17. #17
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    I know this thread is old, but I'm curious about something. What was done with the valve assembly on the firewall once the re-routing of the lines was done? This valve assembly would not be used and just anotehr useless system especially on a track car, but if it is removed there is an open slot in the firewall to that well under the wipers? I guess one could cut a piece of metal to fill that gap?

    Have people removed it or just left it there?

  18. #18
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    Apologies for the partial threadjack but the topic is close enough that a new thread is probably not warranted.

    I am doing the same thing in moving from an S52 to an S54. Does the same thing work? Can I just plug the aluminum tube where it goes to hose at the rear of the head and remove/plug the steel tube coming from behind the t-stat housing that comes out to the other hose? I looped them together when I eliminated the heater core and assume that the core is not part of the manditory flow so... same deal? Plug 'em?
    #54 GTS-3/CM E30 Race car
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  19. #19
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    Here is a quick update on my approach to the hose routing part of this effort. I really didn't want to remove the entire intake if at all possible so after looking at the access and geting my hands to that area but a bit restricted I came up with this plan.

    I removed the CAI, then teh throttle body just moved out of the way over on the fuse box, then the final piece to open up the area was to remove the oil dip stick tube and then I had a good amount of room to all the hoses and the valve selonoid component.

    Here is a look
    image.jpg

    With this access it was a bit tough but I finally got a couple hoses off and then it started to come out easier. Once I got on end of all teh hoses loose I could remove the selenoid piece and will not put this back, no need and it free up some space and weight of course. The insert into the firewall for the hose inlets I need to figure out a plan to plug the plastic hose area not sure what I'll do there yet but plan to just put that piece back in as if the heater was there but seal it up.

    Parts removed
    image.jpg

    With this room, I can access the hoses to join them or even get a hand back to the block to install a blocking plate, so for either path this approach seem to work OK.

  20. #20
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    Manifold comes off quick enough, then you have clear access to replumb that section. Would highly recommend a euro tank or similar "while your in there..."
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  21. #21
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    Quote Originally Posted by badmonkey View Post
    Manifold comes off quick enough, then you have clear access to replumb that section. Would highly recommend a euro tank or similar "while your in there..."
    I choose not to pull the whole thing as I would have prefered to pull it when I have the gaskets to replace on the manifold at the same time as well. This method made the area accessible without too much disassembly. That was my goal, I've got too many other things to get on with.

  22. #22
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    So what do you guys suggest to do with hose # 14 that comes out of the head to the throttle body when deleting the heater core? I understand the block off plate an the rerouting but I'm not sure what to do with this hose.

    Thanks for for any info.

  23. #23
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    So what do you guys suggest to do with hose # 14 that comes out of the head to the throttle body when deleting the heater core? I understand the block off plate an the rerouting but I'm not sure what to do with this hose.

    Thanks for for any info.

  24. #24
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    I used that port that hose 14 connects to (S52) for my aftermarket temp sending unit / guage.
    or just take a plug / bolt and seal up.

  25. #25
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    Quote Originally Posted by eye145 View Post
    I used that port that hose 14 connects to (S52) for my aftermarket temp sending unit / guage.
    or just take a plug / bolt and seal up.
    Perfect! Thanks for the info. I have just plugged it but wanted to make sure that was the correct move.

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